Vanilla Minecraft mobs aren't hard at all. Making the mob speeds a lot faster would give a great challenge. for example endermen are extremely fast and scary to deal with giving players a challenge. With massive mobs being gone I just feel that vanilla mobs are way to easy to kill.
I don't know how doable this is, nor do I particularly dig the idea. Being alone in the wilderness at night without armour and being caught by 5 mobs already seems fine. Perhaps it could be a beacon trait, along with faster spawning? I don't know if that's like... reasonable, though. It seems like an okay idea though! I just don't really dig the idea of it being server-wide. Maybe for some specific mobs, but 100% across the board is a bit much.
